Two stage solenoid operated valve

ABSTRACT

A two stage solenoid operated valve assembly having a first stage poppet movable for seating in a first stage orifice to control fluid flow in a second stage. A second stage poppet is movable for seating in a second stage orifice to control the main flow of fluid. Flow from the first stage orifice to the outlet is through a flow passage which is received within a longitudinal opening extending over the length of the second stage poppet. The second stage poppet moves longitudinally with respect to the flow passage.

United States Patent [191 Zeuner Mar. 26, 1974 TWO STAGE SOLENOIDOPERATED VALVE [75] Inventor:

[73] Assignee: Control concepts, lnc., Newtown,

[22] Filed: Apr. 20, 1972 [21] Appl. No.: 245,929

Kenneth W. Zeuner, Newtown, Pa.

[52] US. Cl. 251/30, 251/44 [51] Int. Cl. F161: 31/383, F16k 31/40 [58]Field of Search 251/30, 44

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 789,241 1/1958Great Britain 251/30 969.108 4/1958 Germany 251/30 1,084,998 7/1960Germany 251/44 Primary ExaminerArnold Rosenthal Attorney, Agent, orFirm-Maleson, Kimmelman & Ratner ABSTRACT A two stage solenoid operatedvalve assembly having a first stage poppet movable for seating in afirst stage orifice to control fluid flow in a second stage. A secondstage poppet is movable for seating in a second stage orifice to controlthe main flow of fluid. Flow from the first stage orifice to the outletis through a flow passage which is received within a longitudinalopening extending over the length of the second stage poppet. The secondstage poppet moves longitudinally with respect to the flow passage.

5 Claims, 3 Drawing Figures TWO STAGE SOLENOID OPERATED VALVE BACKGROUNDOF THE INVENTION 1. Field of the Invention This invention relates to thefield of two stage solenoid operated poppet valves.

2. Prior Art Prior two stage solenoid operated valves have had thedisadvantage of requiring special ports for flow between the first stageorifice and downstream. These special porting requirements have been metby drilling flow channels in the valve housing. However, such channelsin the housing has caused difficulty when multiple valve units are to bemounted. In addition, when valves have been made separate from thehousing, such valves could not be checked out as a total unit.

SUMMARY OF THE INVENTION A two stage solenoid operated valve assemblyhaving a first stage poppet movable between an open and a closed stateseating in a first stage orifice for control ling flow of fluid througha second stage. A second stage poppet is movable between an open stateand a state seating in a second stage orifice for controlling the flowof fluid between the inlet and the outlet of the valve assembly. Thefirst stage poppet is electromagnetically moved between the open andclosed state for actuating, by way of second stage fluid flow, thesecond stage poppet.

The second stage poppet has a longitudinal opening extending over itsentire length. Received within that opening is a flow passage in fluidcommunication with the first stage orifice which provides fluid flowfrom the first stage orifice to the outlet. In this manner, the flowpassage is provided internally of the valve assembly and special portingrequirements in the valve housing are avoided.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a two stagesolenoid operated valve assembly of the present invention;

FIG. 2 is an elevational sectional view of the valve of FIG. 1 takenalong lines 22; and

FIG. 3 is an exploded view of many of the valve elements of FIG. 2.

Referring to FIGS. 1-3, there is shown a two stage solenoid operatedpoppet valve 10. Valve comprises a first stage 11 and a second stage 11awith fluid pressure entering a body or block 14 by way of inlet 14b andexiting by outlet 14c.

First stage 11 is of the normally open poppet type and is described indetail in my copending U.S.Pat. application Ser. No. 218,875 forCONTROLLED AIR GAP IN A SOLENOID VALVE filed Jan. 19, 1972. With firststage 11 normally open, the entire two stage valve 10 operates normallyopen. However, as later described in detail, first stage 11 may benormally closed so that valve 10 operates normally closed. First stage11 comprises a tubular sleeve assembly or housing 12 having threads 12aformed on the outer surface of a lower sleeve section 12d. Threads 12aengage upper internal threads 30a of a plug-in second stage valve body30. First stage sleeve assembly 12 comprises the lower sleeve section12d, the middle sleeve section 12c and an upper sleeve section 12b.Sections 12b and 12d are made of very high magnetically permeablematerial which is defined as ferromagnetic. On the other hand, sectionis made of very low magnetically permeable material such as, forexample, stainless steel. As shown, sections 12b d are rigidly securedtogether, as for example, by welding.

Sections l2b-d together provides an internal cylindrical chamber 16 forhousing a solid cylindrical armature 20 and a tubular pole piece 22having a tubular central chamber 22a. Armature 20 is slideably receivedwithin chamber 16 with an upper section thereof being within section 12band only a lower portion thereof being within section 120. Pole piece223 nests in sealed relation within chamber 16 with a lower flange 22bengaging a lip formed in chamber 16. Most of the pole piece is disposedwithin section 12d with only the upper portion thereof being withinsection 120.

Secured between the bottom surface of piece 22 and a spacer 31 is acontrol orifice assembly 25 having a downwardly extending tube 25dwithin which is a central chamber 25a in fluid communication with outlet140, as shown. Chamber 25a forms in its upper end, an orifice 25b whichmates with a first stage poppet 23. In order to provide properalignment, orifice assembly 25 has a shoulder 256 which is receivedwithin the lower end of chamber 22a and is coaxial therewith.

Poppet 23, preferably made of hard metal of low magnetically permeablematerial, is slideably received within chamber 22a and comprises anupper guide portion 23a and a lower portion 23b. The upper surface ofportion 23a is contacted by the lower face of armature 20 and portion23b terminates in a valve plug 23c. Portion 23a forms a guide havingside walls 23d which contact and slide within chamber 22a and align plug23c into and out of orifice 25b. In addition, walls 23e provide flowpassages for the fluid.

A spring 29 is disposed between and engages the upper surface ofassembly 25 and the lower surface of guide 23a. The spring assures thatthe first stage is maintained normally open. Spring 30 provides sufficient compression or bias to overcome full line upstream pressure atinlet 14b to life poppet 23 from orifice 25b when the valve is switchedfrom its energized to deenergized state. The upstream pressure isapplied to armature 20 and poppet 23 would tend to keep the poppetclosed after the valve is deenergized.

A pair of aligned slots 220 are formed through flange 22b to permitfluid flow. For pressure balance of the upper and lower surfaces ofarmature 20, a longitudinal channel 20a is formed in the outer wall ofthe armature. Accordingly, fluid flow through channel 22a may be tracedthrough passages 23a and channel 20a to the upper surface of armature 20to provide pressure balance.

In the second stage, plug-in valve body 30 is formed having an internalcylindrical chamber 3011 with a sec 0nd stage poppet 32 slideablyreceived therein. The lower end of valve body 30 forms a section ofreduced inner diameter to define an orifice 30b for mating with a valveplug 32a of poppet 32. Spacer 31 is rigidly secured within a reduceddiameter seat in chamber 30a and provides flow passages 31a and acentral opening for receiving tube 25d and second stage spring 33. Tubeor flow passage 25a is centrally received within an inner tubularopening or chamber 32b of poppet 32. Poppet tubular opening 32b has asection 320 of a reduced inner diameter which together with O-ring 60provides a fluid seal around tube 25d. Washer 38 is disposed about tubed and above O-ring 60 to provide a seat for the lower end of a spring33, the upper end of which engages assembly 25. In addition, an O-ring61 is received within the outer surface of poppet 32 above plug 32a toprovide a fluid seal between the outer surface and chamber a. In thismanner, poppet 32 moves vertically with respect to fixed tube d withfluid seals between tube 25d and poppet 32 and between poppet 32 andchamber 30a. Valve body 30 is threadedly received within body or block14.

In the normally open state with electromagnet deenergized, upstreampressure is applied to inlet 14b; poppets 23 and 32 are in theiruppermost positions. Thus, orifice 30b is fully open and upstreampressure flows directly from inlet 14b through channels 34 to outlet140. Spring 29 is effective to maintain poppet 23 in its uppermostposition which causes poppet 32 to be in its uppermost position, asshown in dotted line, for the reasons to be described.

In the normally open state, fluid flow from upstream pressure may betraced by way of inlet 14b, chamber 39 (around body 30), second stagepilot 37, chamber 35 (formed within chamber 30a), flow passages 31a,channels 22c and then through orifice 25b and out the outlet 140.

The pressure in chamber 35 is effective to produce a force tending tomove poppet 32 downwardly and close orifice 30b. This force is equal tothe pressure in chamber 35 times the horizontal cross-sectional area ofchamber 30a minus tube 25d. On the other hand, the force tending to movepoppet 32 upwardly, opening orifice 30b, is dependent on whether poppet32 is closed or opened. If poppet 32 is in its extreme uppermostposition, the differential pressure between inlet 14b and outlet 140 isapplied upwardly to the same horizontal cross-sectional area as thatdefined above. However, if poppet 32 is in its extreme lowermostposition closing orifice 30b, the full line upstream pressure is appliedupwardly only to the horizontal cross-sectional area of a section ofplug 32a that is actually exposed to the upstream pressure. That exposedplug section is between rings 36a b formed on plu'g 32a.

In the normally open state with orifice 25b open, it will be understoodthat pilot 37 acts as a pressure divider between upstream pressure atinlet 14b and downstream pressure at orifice 25b. Pilot 37 is preferablyof smaller diameter than that of orifice 25b. These elements are sizedso that as a result of the pressure dividing action, pressure in chamber35 does not build up sufficiently to provide a downstream force whichwould keep poppet 32 closed against the upward force. Thus, with orifice25b open, the force tending to move poppet 32 upwardly is greater thanthe force tending to move it downwardly. Thus, poppet 32 moves to itsextreme uppermost position with shoulder 32d engaging space 31.

Upon energization of electromagnet 40, as later described in detail,poppet 23 is moved downwardly to close first stage orifice 25b.Accordingly," the pressure in chamber 35 increases and provides asufficient downward force on poppet 32 to close orifice 30b. It will beunderstood that with orifice 25b closed, there is substantially the samepressure in chamber 35 as that applied to plug section 36a-b exposed toupstream pressure. However, in view of the differences in the horizontalcross-sectional areas, the downward force is greater than the upwardforce sufficient to close and maintain poppet 32 closed and seatedagainst orifice 30b.

Upon deenergization of electromagnet 40, spring 29 is effective to pushpoppet 23 upwardly opening orifice 25b. The pressure in chamber 35decreases and poppet 32 is forced downwardly opening orifice 30b for thereasons previously described.

Second stage spring 33 is a light spring and is used to overcomefriction when there is no pressure applied to valve 10. At that time,the spring is effective to maintain poppet 32 closed against seat 30b.

Now that the detailed operation of second stage 1 1a has been described,the detailed operation of first stage 11 will be set forth. A hollowelongated cylindrical electromagnet 40 provides a source of magneticflux and receives in a central opening sleeve assembly 12. Cover 42encloses and protects electromagnet 40 and has a central opening forreceiving therein an upper threaded portion of sleeve section 12b. Cover42 is secured in place by nut 43 which threadedly engages section 12b.Cover 42 as well as armature 20, pole piece 22 and bodies 14 and 32 arefurther of highly magnetically permeable material (ferromagnetic).

A circuit of magnetic flux lines produced by electromagnet 40 whenenergized may be traced as follows. The flux lines flow down throughsleeve section 12b and then across through armature 20 and air gap 50 topole piece 22. The flow continues through sleeve section 12d, body 30and cover 42 with the circuit being completed to section 12b. Sleevesection is made of very low magnetically permeable material and extendsin the area generally adjacent air gap 50 so that section 120 provides agap to the circuit greater than that of gap 50. Accordingly, the circuitof flux lines is directed and concentrated through air gap 50.

In operation of first stage 11, electromagnet 40 has been energized sothat armature 20 has been attracted to pole piece 22. The armatureforces down on poppet 23 so that poppet valve plug 23c is seated withinorifice 25b. Poppet 23 is dimensioned to have a total height(longitudinal length from valve seat to upper surface) so that when itis seated, air gap 50 is compressed to provide a controlled air gap.This controlled air gap is necessary to allow for wear on valve plug 23cand orifice 25b. With the plug seated, if the upper surface of poppet 25were level with pole piece upper surface 22d, then as wear would takeplace, the valve would leak.

In the valve closed state, a substantially high value force is necessaryto keep poppet plug 23c seated against the upstream force of fluid. Thisseating force is achieved by the concentration of flux lines which nowflow across the narrower size controlled air gap and produces asubstantially high value attractive force between armature 20 and polepiece 22. Thus, controlled air gap 50a is dimensioned so that from atypical f-d curve sufficient attractive force will be produced'to seatand maintain seated the poppet against the inlet force of fluid.

In summary, it will now be understood that tube or flow passage 25d isrigidly secured to orifice assembly 25 and thus is fixed with respect toorifice 25b. Thus,

fluid flows from orifice 25b only through tube 25d and then into outlet14c. Tube 25d is received within chamber 32b and this flow passage is atleast of length to extend over the entire longitudinal length of thechamber which extends from the upper surface of shoulder 35d to thelower surface of plug 32a. in this manner, the second stage poppet orplug means 32 is movable longitudinally with respect to tube 25d betweenthe valve open and closed state.

Thus, it will now be understood that separate flow channels in the valvehousing 14 are not required since the flow from orifice 25b to outlet140 is achieved within valve by way of flow passage 25d. In this manner,a multiple of valves 10 may easily be mounted in multiple valve unitsand valve 10 may be checked out by itself as a total unit.

There has now been described how two stage valve 10 operates in anormally open manner. However, two stage valve 10 may also operate as anormally closed valve by using a normally closed first stage. A normallyclosed first stage which may replace the normally open elements areshown and described in my copending US. Pat. application Ser. No.243,633 for NOR- MALLY CLOSED SOLENOID OPERATED VALVE, filed Apr. 13,1972, now US. Pat. No. 3,737,141. Elements 12, 20, 22, 23 and 29 wouldbe replaced by corresponding normally closed elements. The controlorifice assembly 25, electromagnet 40, cover 42, and all of the elementsin second stage 11a herein would remain the same.

What is claimed is:

l. A two stage solenoid operated valve assembly comprising an orificefor a first of said two stages,

first stage plug means movable between a first stage valve state stageand astate seating in and closing said first stage orifice forcontrolling flow of fluid through a second of said two stages.

a second stage orifice opening directly into an outlet of said valveassembly,

second stage plug means movable between a second stage valve open stateand a state seating in and closing said second stage orifice forcontrolling flow of fluid from an inlet to an outlet of said valveassembly,

solenoid means for clectromagnctically moving said first stage plugmeans between said open and closed state for actuating by way of saidcontrol of fluid flow said second stage plug means respectively betweensaid open and closed state,

said second stage plug means having a longitudinal opening extendingthroughout the length thereof, and

a tube in fluid communication with said first stage orifice beingreceived within said longitudinal opening of said second stage plugmeans for providing fluid flow from said first stage orifice directlyinto said outlet during said first stage valve open state. said tubehaving one end rigidly secured with respect to said first stage orificeand having the other end and adjacent tubular surface floating andnonfixed and engaging only said second stage plug means, said other endbeing completely open and located slightly below said second stageorifice within the reduced pressure of the vena contracta.

2. The valve assembly of claim 1 in which said longitudinal opening is acentral chamber formed within said second stage plug means having asection of reduced inner diameter adjacent one end thereof and means forfluid sealing between said reduced inner diameter section and said tube.

3. The valve assembly of claim. 2 in which there is provided secondstage pilot means for providing fluid flow between said inlet and achamber formed adjacent a first end of said second stage plug means forproviding a force of direction tending to move said second stage plugmeans to said valve closed position, and

fluid passageways for providing fluid flow between said chamber and saidfirst stage orifice.

4. The valve assembly of claim 3 in which said second stage pilot meansincludes an orifice of diameter smaller than that of said first stageorifice to provide in said first stage valve open state a pressuredivider so that the pressure in said chamber provides a force less thanthe force applied to a second end of said second stage plug meansthereby opening said second stage valve.

5. The valve assembly of claim 1 in which there is provided first stagepole piece means forming a chamber for slideably receiving at least aminor portion of said first stage plug means.

, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION te 3 {799397Dated March 26 197 4 Inventor(s) Kenneth W. Zeuner It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

In claim 1, line 5 delete "st ate stage" and insert --open state--.

' Signed and sealed this 6th day of August 197 (SEAL) Attest:

MCCOY M. GIBSON, JR. C. MARSHALL DANN Commissioner of Patents AttestingOfficer

1. A two stage solenoid operated valve assembly comprising an orificefor a first of said two stages, first stage plug means movable between afirst stage valve state stage and a state seating in and closing saidfirst stage orifice for controlling flow of fluid through a second ofsaid two stages. a second stage orifice opening directly into an outletof said valve assembly, second stage plug means movable between a secondstage valve open state and a state seating in and closing said secondstage orifice for controlling flow of fluid from an inlet to an outletof said valve assembly, solenoid means for electromagnetically movingsaid first stage plug means between said open and closed state foractuating by way of said control of fluid flow said second stage plugmeans respectively between said open and closed state, said second stageplug means having a longitudinal opening extending throughout the lengththereof, and a tube in fluid communication with said first stage orificebeing received within said longitudinal opening of said second stageplug means for providing fluid flow from said first stage orificedirectly into said outlet during said first stage valve open state, saidtube having one end rigidly secured with respect to said first stageorifice and having the other end and adjacent tubular surface floatingand nonfixed and engaging only said second stage plug means, said otherend being completely open and located slightly below said second stageorifice within the reduced pressure of the vena contracta.
 2. The valveassembly of claim 1 in which said longitudinal opening is a centralchamber formed within said second stage plug means having a section ofreduced inner diameter adjacent one end thereof and means for fluidsealing between said reduced inner diameter section and said tube. 3.The valve assembly of claim 2 in which there is provided second stagepilot means for providing fluid flow between said inlet and a chamberformed adjacent a first end of said second stage plug means forproviding a force of direction tending to move said second stage plugmeans to said valve closed position, and fluid passageways for providingfluid flow between said chamber and said first stage orifice.
 4. Thevalve assembly of claim 3 in which said second stage pilot meansincludes an orifice of diameter smaller than that of said first stageorifice to provide in said first stage valve open state a pressuredivider so that the pressure in said chamber provides a force less thanthe force applied to a second end of said second stage plug meansthereby opening said second stage valve.
 5. The valve assembly of claim1 in which there is provided first stage pole piece means forming achamber for slideably receiving at least a minor portion of said firststage plug means.